A light emitting diode (LED) is an electronically-packaged diode that emits light. LEDs are typically placed on a flexible circuit (also known as flex circuit), a printed circuit board (PCB) or a ceramic board. The amount of light that is generated is a function of the technology used, the size of the chip and the current applied. Light is generally emitted off the top or side of the electronic package. Light that is not reflected to a desired target is wasted energy. Managing the light effectively can reduce the energy required and reduce the overall heat in the system. Reflectivity is critical to get the most lumens (a measure of brightness) out of a LED by utilizing all available light. In the current LED industry, the surface reflectivity of LED circuit should be at least 70%. For example, typical white solder masks can provide a specular reflectivity of around 85%.
A challenge in the LED industry is to devise a visually appealing device such as a display sign or electronics display gadgets that are aesthetically appealing and have an enhanced brightness performance in a cost-effective manner.
In one existing approach, a paint layer or an organic material coating is used to achieve reflection in lighting applications. However, the reflectivity of these paint layers is usually not uniform due to the heterogeneous nature of the material, and corrosion and deterioration of the material in the course of time.
In another existing approach, aluminium or silver coatings are used as reflection sheets, and the reflection layer is protected by transparent polymer film. However, these coatings may be easily corroded by atmospheric moisture.
A need therefore exists to provide a reflection sheet that seeks to address at least some of the above problems, or provide a useful alternative.